Leg swelling and pain may be related to physiological factors such as prolonged standing, strenuous exercise, and pathological factors such as trauma and vascular diseases. 1. Physiological factors: standing for a long time can lead to poor blood circulation in the lower limbs, resulting in leg swelling and pain, high-intensity exercise, the body produces too many metabolic products, a large number of lactic acid buildup, can also cause leg swelling and pain, these are physiological factors, can be gradually relieved after rest. 2. Trauma: due to violence and other traumatic injuries, can lead to muscle strains, ligament tears and other soft tissue injuries, local microvascular rupture, blood seepage, resulting in local soft tissue bruising and swelling, leg swelling and pain phenomenon. 3. Vascular diseases: varicose veins of the lower limbs, deep vein thrombosis of the lower limbs and other factors can lead to blood circulation obstacles in the lower limbs, resulting in leg swelling and pain, which can also be accompanied by sensory abnormalities, skin color and temperature abnormalities and other phenomena. There are many other causes of leg swelling and pain, which need to improve the lower limb vascular ultrasound, MRI and other tests to confirm the diagnosis, and it is recommended that the patient consult a doctor in time to clarify the cause of the disease and then carry out targeted treatment.